Display apparatus including touch sensing unit with low-density silicon nitride layer

ABSTRACT

A display apparatus includes an organic light emitting display panel including a thin film encapsulation layer, a first conductive layer directly on the thin film encapsulation layer, at least one inorganic layer on the thin film encapsulation layer and having a density of about 2.05 g/cm3 to about 2.4 g/cm3, and a window on the at least one inorganic layer. In the display apparatus according to embodiments of the present disclosure, the generation of bubbles may be suppressed or reduced.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is a continuation of U.S. patent applicationSer. No. 15/496,803, filed Apr. 25, 2017, which claims priority to andthe benefit of Korean Patent Application No. 10-2016-0081054, filed onJun. 28, 2016, the disclosures of which are hereby incorporated byreference herein in their entireties.

BACKGROUND

One or more aspects of embodiments of the present disclosure hereinrelate to a display apparatus, and more particularly, to a displayapparatus including a high-density inorganic layer.

Various display apparatuses that may be utilized in multimedia devicessuch as televisions, mobile phones, tablet computers, navigationdevices, and game consoles are being developed. A display apparatusoften includes a keyboard or a mouse as an input unit. Also, in recentyears, a display apparatus may include a touch panel as an input unit.

Display apparatuses undergo reliability assessment under severeconditions before being released to the market. Only products that passthe reliability assessment are then sold to consumers.

SUMMARY

One or more aspects of embodiments of the present disclosure aredirected toward a display apparatus that shows improved reliability whenin severe conditions.

An embodiment of the inventive concept provides a display apparatusincluding an organic light emitting display panel, a window, a firstconductive layer, a second conductive layer, at least one inorganiclayer, and an organic layer. The organic light emitting display panelmay include a base layer, a circuit layer on the base layer, a lightemitting element layer on the circuit layer, and a thin filmencapsulation layer on the light emitting element layer. The firstconductive layer may be directly on the thin film encapsulation layer,the second conductive layer may be on the thin film encapsulation layer,where the second conductive layer may be on a layer other than the firstconductive layer. At least one inorganic layer may be on the thin filmencapsulation layer and may have a density of about 2.05 g/cm³ to about2.4 g/cm³, and the organic layer may be on the at least one inorganiclayer. The window may face the organic light emitting display panel withthe first conductive layer, the at least one inorganic layer, and theorganic layer between the window and the organic light emitting displaypanel.

In an embodiment, the at least one inorganic layer may include a siliconnitride layer having a density of about 2.05 g/cm³ to about 2.4 g/cm³.

In an embodiment, the thin film encapsulation layer may include: aplurality of inorganic thin films; and at least one organic thin filmbetween the plurality of inorganic thin films.

In an embodiment, the at least one inorganic layer may include: a firstinorganic layer between the first conductive layer and the secondconductive layer; and a second inorganic layer on the first conductivelayer and the second conductive layer.

In an embodiment, the at least one inorganic layer may be between thefirst conductive layer and the second conductive layer, and the organiclayer may be directly on the second conductive layer.

In an embodiment, the display apparatus may further include an organicadhesion layer configured to couple the window to the organic lightemitting display panel.

In an embodiment, the at least one inorganic layer may be directly onthe second conductive layer, and the display apparatus may furtherinclude an intermediate insulation layer between the first conductivelayer and the second conductive layer.

In an embodiment, the organic layer may include an organic adhesionlayer configured to couple the window to the organic light emittingdisplay panel.

In an embodiment, the display apparatus may further include a polarizingfilm between the at least one inorganic layer and the window.

In an embodiment, the first conductive layer may include bridge parts,and the second conductive layer may include connection partsrespectively crossing the bridge parts, first touch sensor parts, wherethe connection parts respectively connect adjacent first touch sensorparts, and second touch sensor parts, where the bridge partsrespectively connect adjacent touch sensor parts.

In an embodiment, the light emitting element layer may include anemission area and a non-emission area adjacent to the emission area, andeach of the first touch sensor parts and the second sensor parts mayhave a mesh pattern and may overlap the non-emission area.

In an embodiment, the first conductive layer may include connectionparts, first touch sensor parts, where the connection parts respectivelyconnect adjacent first touch sensor parts, and second touch sensor partsspaced apart from the first touch sensor parts. The second conductivelayer may include bridge parts, the bridge parts respectively connectingadjacent second touch sensor parts and respectively crossing theconnection parts.

In an embodiment, the first conductive layer may include firstconnection parts and first touch sensor parts, the first connectionparts respectively connecting adjacent first touch sensor parts. Thesecond conductive layer may include second connection parts respectivelycrossing the first connection parts, and second touch sensor parts,where the second connection parts respectively connect adjacent secondtouch sensor parts.

In an embodiment, first light reflected by the first conductive layerand second light reflected by the second conductive layer may have aphase difference of about 180° therebetween.

In an embodiment, the at least one inorganic layer may include: a firstinorganic layer between the first conductive layer and the secondconductive layer and a second inorganic layer on the first conductivelayer and the second conductive layer.

In an embodiment, the window may include a plastic film. The organiclayer may include an organic adhesion layer contacting the window.

In an embodiment of the inventive concept, a display apparatus mayinclude an organic light emitting display panel, a touch sensing unit,an organic adhesion layer, and a window. The organic light emittingdisplay panel may include a base layer, a circuit layer on the baselayer, a light emitting element layer on the circuit layer, and anencapsulation layer on the light emitting element layer. The touchsensing unit may be directly on the thin film encapsulation layer, theorganic adhesion layer may be on the touch sensing unit. The window mayface the organic light emitting display panel, with the touch sensingunit and the organic adhesion layer being between the window and theorganic light emitting display panel.

The touch sensing unit may include: conductive patterns directly on thethin film encapsulation layer; and an insulation layer covering theconductive patterns. The insulation layer may include an inorganic layerhaving a density of about 2.05 g/cm³ to about 2.4 g/cm³.

In an embodiment of the inventive concept, a display apparatus mayinclude: a display panel including a first inorganic layer; firstconductive patterns directly on the first inorganic layer; a firstinsulation layer covering the first conductive patterns; secondconductive patterns directly on the first insulation layer; secondinsulation layer covering the second conductive patterns; an organicadhesion layer on the second insulation layer; and a window facing thedisplay panel, with the organic adhesion layer being between the windowand the display panel. At least one of the first insulation layer andthe second insulation layer may include an inorganic layer having adensity of about 2.05 g/cm³ to about 2.4 g/cm³.

In an embodiment of the inventive concept, the inorganic layer includedin the at least one of the first insulation layer and the secondinsulation layer may include a silicon nitride layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the inventive concept, and are incorporated in andconstitute a part of this specification. The drawings illustrate exampleembodiments of the inventive concept and, together with the description,serve to explain principles of the inventive concept.

In the drawings:

FIG. 1A is a perspective view illustrating a first operation mode of adisplay apparatus according to an embodiment of the inventive concept;

FIG. 1B is a perspective view illustrating a second operation mode ofthe display apparatus according to an embodiment of the inventiveconcept;

FIG. 1C is a perspective view illustrating a third operation mode of thedisplay apparatus according to an embodiment of the inventive concept;

FIG. 2 is a cross-sectional view of the display apparatus according toan embodiment of the inventive concept;

FIGS. 3A and 3B are perspective views of a display apparatus accordingto an embodiment of the inventive concept;

FIG. 4A is a cross-sectional view of a display module according to anembodiment of the inventive concept;

FIG. 4B is a plan view of an organic light emitting display panelaccording to an embodiment of the inventive concept;

FIG. 4C is an equivalent circuit diagram of a pixel according to anembodiment of the inventive concept;

FIGS. 4D and 4E are partial cross-sectional views of an organic lightemitting display panel according to an embodiment of the inventiveconcept;

FIGS. 5A to 5C are cross-sectional views of a thin film encapsulationlayer according to one or more embodiments of the inventive concept;

FIG. 6A is a cross-sectional view of a touch sensing unit according toan embodiment of the inventive concept;

FIGS. 6B to 6E are plan views of the touch sensing unit according to oneor more embodiments of the inventive concept;

FIG. 7A is a partial enlarged view of an area AA of FIG. 6E;

FIG. 7B is a partial cross-sectional view of FIG. 7A;

FIG. 7C is a partial cross-sectional view of FIG. 6A;

FIG. 8A is a cross-sectional view illustrating bubble defects occurringin the display apparatus;

FIG. 8B is a photograph illustrating the bubble defects occurring in thedisplay apparatus;

FIG. 9 is a graph illustrating bubble defects depending on a layerdensity;

FIG. 10A is a cross-sectional view of a display apparatus according toan embodiment of the inventive concept;

FIG. 10B is an enlarged cross-sectional view of the display apparatusaccording to an embodiment of the inventive concept; and

FIG. 11 is a cross-sectional view of a display device according to anembodiment of the inventive concept.

DETAILED DESCRIPTION

Hereinafter, embodiments of the inventive concept will be described withreference to the accompanying drawings. In this specification, it willalso be understood that when one component (or region, layer, portion)is referred to as being “on”, “connected to”, or “coupled to” anothercomponent, it can be directly on/connected to/coupled to the onecomponent, or one or more intervening components may also be present.

Like reference numerals refer to like elements throughout. Also, in thefigures, the thickness, ratio, and dimensions of components areexaggerated for clarity of illustration. The term “and/or” includes anyand all combinations of one or more of the associated listed items.Expressions such as “one of” and “selected from,” when preceding a listof elements, modify the entire list of elements and do not modify theindividual elements of the list. Further, the use of “may” whendescribing embodiments of the present invention refers to “one or moreembodiments of the present invention.”

It will be understood that although the terms “first” and “second” areused herein to describe various elements, these elements should not belimited by these terms. The terms are only used to distinguish onecomponent from other components. For example, an element referred to as“a first element” in one embodiment can be referred to as “a secondelement” in another embodiment, without departing from the scope of theappended claims. The terms in a singular form may include plural formsunless expressly indicated otherwise.

Also, the terms “under”, “below”, “above”, “upper”, and the like areused herein for explaining relationship between one or more componentsillustrated in the drawings. As such, these terms may be relative termsdescribing the positions of components in the drawings, but thepositions of components are not limited thereto.

It will be further understood that the meaning of the terms “include” or“comprise” may specify a property, a fixed number, a step, an operation,an element, a component or a combination thereof, but does not excludeother properties, fixed numbers, steps, operations, elements, componentsor combinations thereof.

FIG. 1A is a perspective view illustrating a first operation mode of adisplay apparatus DD according to an embodiment of the inventiveconcept. FIG. 1B is a perspective view illustrating a second operationmode of the display apparatus DD according to an embodiment of theinventive concept. FIG. 1C is a perspective view illustrating a thirdoperation mode of the display apparatus DD according to an embodiment ofthe inventive concept.

As illustrated in FIG. 1A, in a first operation mode, a display surfaceIS on which an image IM is displayed is parallel to a surface that isdefined by a first directional axis DR1 and a second directional axisDR2. A direction normal to the display surface IS (i.e. a thicknessdirection of the display apparatus DD) is indicated as a thirddirectional axis DR3. A front surface (or top surface) and a rearsurface (or bottom surface) of the display apparatus are positionedalong the third directional axis DR3. However, directions indicated asthe first to third directional axes DR1, DR2, and DR3 may be a relativeconcept and are not limited to the first to third directional axesillustrated in the drawings. Hereinafter, for convenience ofexplanation, the first to third directions, as these terms are usedherein, may be indicated by the first to third directional axes DR1,DR2, and DR3 and designated by the same reference numerals,respectively.

FIGS. 1A to 1C illustrate a foldable display apparatus as an example ofthe flexible display apparatus DD. In some embodiments, the displayapparatus DD may be a rollable or bendable display apparatus, but notspecifically limited thereto. Although a flexible display apparatus isillustrated in the current embodiment, the embodiment of the inventiveconcept is not limited thereto. The display apparatus DD according tothe current embodiment may be a flat rigid display apparatus. Theflexible display apparatus DD according to an embodiment of theinventive concept may be used in large-sized electronic devices such astelevisions and monitors and small and middle-sized electronic devicessuch as mobile phones, tablet PC, navigation units for vehicles, gameconsoles, and smart watches.

As illustrated in FIG. 1A, the display surface IS of the flexibledisplay apparatus DD may include a plurality of areas. The flexibledisplay apparatus DD include a display area DD-DA on which the image IMis displayed and a non-display area DD-NDA that is adjacent to thedisplay area DD-DA. The non-display area DD-NDA may be an area on whichan image is not displayed. FIG. 1A illustrates a flower vase as anexample of the image IM. For example, the display area DD-DA may have arectangular shape. The non-display area DD-NDA may surround the displayarea DD-DA. However, the embodiment of the inventive concept is notlimited thereto. For example, the display area DD-DA and the non-displayarea DD-NDA may have various shapes and positions relative to oneanother.

As illustrated in FIGS. 1A to 1C, the display apparatus DD may include aplurality of areas defined according to operation modes. The displayapparatus DD may include a bent area BA that is bent along a bendingaxis BX, a first non-bent area NBA1 that is not bent, and a secondnon-bent area NBA2 that is not bent. As illustrated in FIG. 1B, thedisplay apparatus DD may be bent inward, such that the display surfaceIS of the first non-bent area NBA1 and the display surface IS of thesecond non-bent area NBA2 face each other. As illustrated in FIG. 1C,the display apparatus DD may also be bent outward, such that the displaysurface IS is exposed to the outside.

In an embodiment of the inventive concept, the display apparatus DD mayinclude a plurality of bent areas BA. In addition, the bent areas BA maybe defined on the display apparatus DD in accordance with user'soperations for manipulating the display apparatus DD. For example, thebent areas BA may be positioned parallel to the first directional axisDR1 or may extend in a diagonal direction. An area of the bent area BAmay not be fixed, but may instead be determined according to a curvatureradius thereof. In an embodiment of the inventive concept, the displayapparatus DD may have a shape in which only operation modes of FIGS. 1Aand 1B are repeated.

FIG. 2 is a cross-sectional view of the display apparatus DD accordingto an embodiment of the inventive concept. FIG. 2 illustrates across-section defined by the second directional axis DR2 and the thirddirectional axis DR3.

As illustrated in FIG. 2, the display apparatus DD includes a protectionfilm PM, a display module DM, an optical member LM, a window WM, a firstadhesion member AM1, a second adhesion member AM2, and a third adhesionmember AM3. The display module DM is disposed between the protectionfilm PM and the optical member LM. The optical member LM is disposedbetween the display module DM and the window WM. The first adhesionmember AM1 is coupled to the display module DM and the protection filmPM, the second adhesion member AM2 is coupled to the display module DMand the optical member LM, and the third adhesion member AM3 is coupledto the optical member LM and the window WM.

The protection film PM protects the display module DM. The protectionfilm PM provides a first outer surface OS-L that is exposed to theoutside and an adhesion surface (opposite the first outer surface OS-L)that adheres to the first adhesion member AM1. The protection film PMmay prevent or reduce external moisture from being permeated into thedisplay module DM and may absorb an external impact.

The protection film PM may include a plastic film as a base layer. Theprotection film PM may include at least one selected frompolyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI),polyethylene naphthalate (PEN), polyethylene terepthalate (PET),polyphenylene sulfide (PPS), polyallylate, polyimide (PI), polycarbonate(PC), poly(arylene ether sulfone), and combinations thereof.

A material for forming the protection film PM is not limited to plasticresins. For example, the protection film PM may include anorganic/inorganic composite material. In some embodiments, theprotection film PM may include a porous organic layer and an inorganicmaterial that is filled into pores of the organic layer. The protectionfilm PM may further include a functional layer disposed (e.g.,positioned) on a plastic film. The functional layer may include a resinlayer. The functional layer may be formed in by coating. In anembodiment of the inventive concept, the protection film PM may beomitted.

The window WM may protect the display module DM against external impactand may provide an input surface for a user. The window WM includes asecond outer surface OS-U that is exposed to the outside and an adhesionsurface (opposite the second outer surface OS-U) that adheres to thethird adhesion member AM3. The display surface IS shown in FIGS. 1A to1C may be the second outer surface OS-U.

The window WM may include a plastic film. In some embodiments, thewindow WM may include a multilayered structure. For example, the windowWM may have a multilayered structure including two or more selected froma glass substrate, a plastic film, and a plastic substrate. The windowWM may further include a bezel pattern. The multilayered structure maybe formed through a continuous process (e.g., continuous depositionprocess) or an adhesion process using an adhesion layer.

The optical member LM may reduce reflexibility (e.g., reflection) ofexternal light. The optical member LM may include a polarizing film. Theoptical member LM may include a phase difference film. In an embodimentof the inventive concept, the optical member LM may be omitted.

The display module DM may include an organic light emitting displaypanel DP and a touch sensing unit TS. The touch sensing unit TS may bedirectly disposed on the organic light emitting display panel DP. Inthis specification, the term “an A1 component is directly disposed on aB1 component” refers to the A1 and B1 components that are being formedthrough the continuous process (e.g., continuous deposition process). Inother words, an adhesion layer is not placed between the A1 componentand the B1 component.

The organic light emitting display panel DP may generate an image (seee.g., reference symbol IM of FIG. 1A) corresponding to inputted imagedata. The organic light emitting display panel DP may include a firstdisplay panel surface BS1-L and a second display panel surface BS1-U,which face each other in the thickness direction DR3. Although anexample of the organic light emitting display panel DP is described inthe current embodiment, the embodiment of the inventive concept is notlimited to the above-described display panel.

The touch sensing unit TS may be configured to acquire coordinateinformation of an external input. In some embodiments, the touch sensingunit TS may sense an external input in a capacitive manner (e.g., thetouch sensing unit TS may utilize capacitive sensing).

The display module DM according to an embodiment of the inventiveconcept may further include a reflection prevention layer. Thereflection prevention layer may include a color filer or a laminatedstructure of a conductive layer/an insulation layer/a conductive layer.The reflection prevention layer may absorb, destructively interferewith, or polarize light incident from the outside in order to reducereflectance of external light. In some embodiments, the reflectionprevention layer may perform the function of the optical member LM.

Each of the first adhesion member AM1, the second adhesion member AM2,and the third adhesion member AM3 may be an organic adhesion layer suchas an optically clear adhesive film (OCA), an optically clear resin(OCR), and/or a pressure sensitive adhesive film (PSA). The organicadhesion layer may include an adhesion material such as apolyurethane-based material, a polyacrylic-based material, apolyester-based material, a polyepoxy-based material, and/or a polyvinylacetate-based material. As such, the organic adhesion layer maycorrespond to one of organic layers. As described below, the organicadhesion layer may cause the generation of bubbles.

The display apparatus DD may further include a frame structure thatsupports the functional layers to maintain the configuration illustratedin FIGS. 1A to 1C. The frame structure may include a joint structure ora hinge structure.

FIGS. 3A and 3B are perspective views of a display apparatus DD-1according to an embodiment of the inventive concept. FIG. 3A illustratesthe display apparatus DD-1 that is in a spread-out state, and FIG. 3Billustrates the display apparatus DD-1 that is in a bent state.

The display apparatus DD-1 may include one bent area BA and one non-bentarea NBA. For example, the bent area BA may be positioned in thenon-display area DD-NDA of the display apparatus DD-1. However, in anembodiment of the inventive concept, the position of the bent area ofthe display apparatus DD-1 may be changed.

The display apparatus DD-1 according to an embodiment of the inventiveconcept may have a fixed shape in which it may operate, unlike thedisplay apparatus DD of FIGS. 1A to 1C. For example, the displayapparatus DD-1 may operate in the bent state as illustrated in FIG. 3B.The display apparatus DD-1 may be fixed to a frame in the bent state,and the frame may be coupled to a housing of an electronic device.

The display apparatus DD-1 according to an embodiment of the inventiveconcept may have the same (or substantially the same) structure as thatof the display apparatus DD of FIG. 2. However, the non-bent area NBAand the bent area BA of the display apparatus DD-1 may have laminatedstructures different from each other. For example, the non-bent area NBAof the display apparatus DD-1 may have the same cross-sectionalstructure as that of the display apparatus DD of FIG. 2, and the bentarea BA of the display apparatus DD-1 may have a cross-sectionalstructure different from that of the display apparatus DD of FIG. 2. Anoptical member LM and the window WM of the display apparatus DD-1 maynot be disposed in the bent area BA. For example, the optical member LMand the window WM may be disposed only in the non-bent area NBA of thedisplay apparatus DD-1. Also, the second adhesion member AM2 and thethird adhesion member AM3 may not be disposed in the bent area BA of thedisplay apparatus DD-1.

FIG. 4A is a cross-sectional view of a display module DM according to anembodiment of the inventive concept. FIG. 4B is a plan view of theorganic light emitting display panel DP according to an embodiment ofthe inventive concept. FIG. 4C is an equivalent circuit diagram of apixel PX according to an embodiment of the inventive concept. FIGS. 4Dand 4E are partial cross-sectional views of the organic light emittingdisplay panel DP according to an embodiment of the inventive concept.

As illustrated in FIG. 4A, the organic light emitting display panel DPincludes a base layer SUB, a circuit layer DP-CL disposed on the baselayer SUB, a light emitting element layer DP-OLED, and a thin filmencapsulation layer TFE. The base layer SUB may include at least oneplastic film. In some embodiments, the base layer SUB may include aplastic substrate, a glass substrate, a metal substrate, and/or anorganic/inorganic composite substrate as a flexible substrate.

The circuit layer DP-CL may include a plurality of insulation layers, aplurality of conductive layers, and/or a semiconductor layer. Theplurality of conductive layers of the circuit layer DP-CL may constitutesignal lines or a control circuit of a pixel. The light emitting elementlayer DP-OLED may include organic light emitting diodes. The thin filmencapsulation layer TFE may seal the light emitting element layerDP-OLED. The thin film encapsulation layer TFE may include at least twoinorganic thin films and at least one organic thin film disposed betweenthe at least two inorganic thin films. The inorganic thin films mayprotect the light emitting element layer DP-OLED againstmoisture/oxygen, and the organic thin film may protect the lightemitting element layer DP-OLED against foreign substances such as dustparticles.

The touch sensing unit TS may be directly disposed on the thin filmencapsulation layer TFE. The touch sensing unit TS may include touchsensors and touch signal lines. The touch sensors and the touch signallines may each independently have a single layer or multilayeredstructure.

The touch sensors and the touch signal lines may each independentlyinclude indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), and/or indium tin zinc oxide (ITZO), PEDOT, a metal nano wire,and/or graphene. In some embodiments, the touch sensors and the touchsignal lines may each independently include a metal layer formed of, forexample, molybdenum, silver, titanium, copper, aluminum, and/or an alloythereof. The touch sensors and the touch signal lines may eachindependently have the same single-layer structure or may have layerstructures different from each other. A more detailed description of thetouch sensing unit TS will be provided later.

As illustrated in FIG. 4A, the organic light emitting display panel DPmay include a display area DA and a non-display area NDA on a plane. Thedisplay area DA and the non-display area NDA of the organic lightemitting display panel DP may correspond to the display area DD-DA andthe non-display area DD-NDA of the display apparatus DD, respectively.However, embodiments of the present invention are not limited to thedisplay area DA and the non-display area NDA of the organic lightemitting display panel DP respectively corresponding to the display areaDD-DA and the non-display area DD-NDA of the display apparatus DD. Forexample, the display area DA and the non-display area NDA of the organiclight emitting display panel DP may be changed according to astructure/design of the organic light emitting display panel DP.

As illustrated in FIG. 4B, the organic light emitting display panel DPmay include a plurality of signal lines SGL and a plurality of pixelsPX. An area on which the plurality of pixels PX are disposed may bedefined as the display area DA. In the current embodiment, thenon-display area NDA may be defined along an edge of the display areaDA.

The plurality of signal lines SGL may include gate lines GL, data linesDL, a power line PL, and a control signal line CSL. The gate lines GLmay be connected to corresponding pixels PX of the plurality of pixelsPX, and the data lines DL may be connected to corresponding pixels PX ofthe plurality of pixels PX, respectively. The power line PL may beconnected to the plurality of pixels PX. A gate driving circuit DCV towhich the gate lines GL are connected may be disposed (e.g., positioned)on one side of the non-display area NDA. The control signal line CSL mayprovide control signals to the gate driving circuit DCV.

Portions of the gate lines GL, the data lines DL, the power line PL, andthe control signal line CSL may be disposed on the same layer, and otherportions may be disposed on layers different from each other. Each ofthe gate lines GL, the data lines DL, the power line PL, and the controlsignal line CSL may include a signal line unit and a signal pad unitconnected to an end of the signal line unit. A control part unit CSL-P,a data pad unit DL-P, and a power pad unit PL-P are illustrated as anexample of the signal pad unit. In some embodiments, a gate pad unit mayalso overlap the gate driving circuit DCV and may be connected to thegate driving circuit DCV.

FIG. 4C illustrates an example of a pixel PX connected to one gate lineGL, one data line DL, and the power line PL. However, the embodiment ofthe inventive concept is not limited to the configuration of the pixelPX illustrated in the figure. For example, the pixel PX may be varied inconfiguration.

The pixel PX includes an organic light emitting diode OLED as a displaydevice. The organic light emitting diode OLED may be a top emissiondiode or a bottom emission diode. The pixel PX includes a firsttransistor TFT1 (e.g., a switching transistor), a second transistor TFT2(e.g., a driving transistor), and a capacitor CAP as a circuit unit fordriving the organic light emitting diode OLED.

The first transistor TFT1 outputs a data signal applied to the data lineDL in response to a scanning signal applied to the gate line GL. Thecapacitor CAP charges a voltage corresponding to the data signalreceived from the first transistor TFT1.

The second transistor TFT2 is connected to the organic light emittingdiode OLED. The second transistor TFT2 controls driving current flowingthrough the organic light emitting diode OLED to correspond to a chargeamount stored in the capacitor CAP. The organic light emitting diodeOLED emits light during a turn-on period of the second transistor TFT2.

FIG. 4D is a cross-sectional view of portions corresponding to the firsttransistor TFT1 and the capacitor CAP of the equivalent circuit of FIG.4C. FIG. 4E is a cross-sectional view of portions corresponding to thesecond transistor TFT2 and the organic light emitting diode OLED of theequivalent circuit of FIG. 4C.

As illustrated in FIGS. 4D and 4E, the circuit layer DP-CL is disposedon the base layer SUB. A semiconductor pattern AL1 (hereinafter,referred to as a first semiconductor pattern) of the first transistorTFT1 and a semiconductor pattern AL2 (hereinafter, referred to as asecond semiconductor pattern) of the second transistor TFT2 may bedisposed on the base layer SUB. The first and second semiconductorpatterns AL1 and AL2 may be the same or different, and may eachindependently be selected from amorphous silicon, polysilicon, and ametal oxide semiconductor.

In some embodiments, functional layers may be further disposed on onesurface of the base layer SUB. The functional layers may include atleast one selected from a barrier layer and a buffer layer. The firstand second semiconductor patterns AL1 and AL2 may each independently bedisposed on the barrier layer and/or the buffer layer.

A first insulation layer 12 covering the first and second semiconductorpatterns AL1 and AL2 is disposed on the base layer SUB. The firstinsulation layer 12 includes an organic layer and/or an inorganic layer.For example, the first insulation layer 12 may include a plurality ofinorganic thin films. The plurality of inorganic thin films may includea silicon nitride layer and/or a silicon oxide layer.

A control electrode GE1 (hereinafter, referred to as a first controlelectrode) of the first transistor TFT1 and a control electrode GE2(hereinafter, referred to as a second control electrode) of the secondtransistor TFT2 may each independently be disposed on the firstinsulation layer 12. A first electrode E1 of the capacitor CAP isdisposed on the first insulation layer 12. The first control electrodeGE1, the second control electrode GE2, and the first electrode E1 mayeach independently be manufactured by the same photolithograph processas that of the gate lines GL (illustrated in FIG. 4C). For example, thefirst electrode E1 may be formed of the same material as the gate linesGL, have the same laminated structure as the gate lines GL, and bedisposed on the same layer as the gate lines GL.

A second insulation layer 14 covering the first and second controlelectrodes GE1 and GE2 and the first electrode E1 is disposed on thefirst insulation layer 12. The second insulation layer 14 includes anorganic layer and/or an inorganic layer. For example, the secondinsulation layer 14 may include a plurality of inorganic thin films. Theplurality of inorganic thin films may include a silicon nitride layerand/or a silicon oxide layer.

The data lines DL (illustrated in FIG. 4C) may be disposed on the secondinsulation layer 14. An input electrode SE1 (hereinafter, referred to asa first input electrode) and an output electrode DE1 (hereinafter,referred to as a first output electrode) of the first transistor TFT1may be disposed on the second insulation layer 14. An input electrodeSE2 (hereinafter, referred to as a second input electrode) and an outputelectrode DE2 (hereinafter, referred to as a second output electrode) ofthe second transistor TFT2 may be disposed on the second insulationlayer 14. The first input electrode SE1 is branched from a correspondingdata line of the data lines DL. The power line PL (illustrated in FIG.4C) may be disposed on the same layer as the data lines DL. The secondinput electrode SE2 may be branched from the power line PL.

A second electrode E2 of the capacitor CAP may be disposed on the secondinsulation layer 14. The second electrode E2 may be manufactured by thesame photolithograph process as that of each of the data lines DL andthe power line PL. For example, the second electrode E2 may be formed ofthe same material, have the same structure, and be disposed on the samelayer as that of each of the data line DL and the power line PL.

The first input electrode SE1 and the first output electrode DE1 areconnected to the first semiconductor pattern AL1 through first andsecond through holes CH1 and CH2, which pass through the first andsecond insulation layers 12 and 14. The first output electrode DE1 maybe electrically connected (e.g., coupled) to the first electrode E1. Forexample, the first output electrode DE1 may be connected to the firstelectrode E1 through a through hole (not shown) passing through thesecond insulation layer 14. The second input electrode SE2 and thesecond output electrode DE2 are connected to the second semiconductorpattern AL2 through third and fourth through holes CH3 and CH4, whichpass through the first and second insulation layers 12 and 14. Accordingto another embodiment of the inventive concept, each of the first andsecond transistors TFT1 and TFT2 may be formed to have a bottom gatestructure.

A third insulation layer 16 covering the first input electrode SE1, thefirst output electrode DE1, the second input electrode SE2, and thesecond output electrode DE2 may be disposed on the second insulationlayer 14. The third insulation layer 16 includes an organic layer and/oran inorganic layer. For example, the third insulation layer 16 mayinclude an organic material to provide a substantially flat surface.

In some embodiments, one of the first, second, and third insulationlayers 12, 14, and 16 may be omitted according to the circuit structureof the pixel. Each of the second and third insulation layers 14 and 16may be an interlayer dielectric layer. The interlayer dielectric layermay be disposed between a lower conductive pattern and an upperconductive pattern to insulate the conductive patterns from each other.

As illustrated in FIGS. 4D and 4E, the light emitting element layerDP-OLED is disposed on the third insulation layer 16. In someembodiments, a pixel defining layer PXL and the organic light emittingdiode OLED are disposed on the third insulation layer 16. For example,an anode AE of the organic light emitting diode OLED may be disposed onthe third insulation layer 16. The anode AE is connected to the secondoutput electrode DE2 through a fifth through hole CH5 passing throughthe third insulation layer 16. An opening OP is defined in the pixeldefining layer PXL. The opening OP of the pixel defining layer PXLexposes at least a portion of the anode AE.

The light emitting element layer DP-OLED may include an emission areaPXA and a non-emission area NPXA that is adjacent to the emission areaPXA. For example, the non-emission area NPXA may surround the emissionarea PXA. In the current embodiment, the emission area PXA is defined tocorrespond to the anode AE. However, the embodiment of the inventiveconcept is not limited to the above-described emission area PXA. In someembodiments, the area may be defined as the emission area PXA so long asthe light is emitted from the area. In some embodiments, the emissionarea PXA may be defined to correspond to a portion of the anode AE,which is exposed by the opening OP.

A hole control layer HCL may be commonly defined (e.g., positioned) inthe emission area PXA and the non-emission area NPXA. In someembodiments, a common layer such as the hole control layer HCL may becommonly disposed on the plurality of pixels PX (illustrated in FIG.4B).

An organic light emitting layer EML is disposed on the hole controllayer HCL. The organic light emitting layer EML may be disposed only inan area corresponding to the opening OP. For example, the organic lightemitting layer EML may be separated from each of the plurality of pixelsPX.

An electronic control layer ECL is disposed on the organic lightemitting layer EML. A cathode CE is disposed on the electronic controllayer ECL. In some embodiments, the cathode CE is commonly disposed on(e.g., over) the plurality of pixels PX.

Although a patterned organic light emitting layer EML is illustrated asan example in the current embodiment (e.g., there is a separate organiclight emitting layer EML for each pixel PX), the organic light emittinglayer EML may also be commonly disposed on the plurality of pixels PX.In some embodiments, the organic light emitting layer EML may emit whitelight. Also, the organic light emitting layer EML may have a multilayerstructure.

In the current embodiment, the thin film encapsulation layer TFEdirectly covers the cathode CE. In some embodiments, a capping layercovering the cathode CE may be further disposed, and the thin filmencapsulation layer TFE may directly cover the capping layer.

FIGS. 5A to 5C are cross-sectional views of thin film encapsulationlayers TFE1, TFE2, and TFE3 according to one or more embodiments of theinventive concept. Hereinafter, the thin film encapsulation layers TFE1,TFE2, and TFE3 according to embodiments of the inventive concept will bedescribed with reference to FIGS. 5A to 5C.

As illustrated in FIG. 5A, the thin film encapsulation layer TFE1 mayinclude n inorganic thin films (e.g., the inorganic thin films may beincluded in a range of IOL1 to IOLn), with the first inorganic thin filmIOL1 contacting the cathode CE (cathode CE is illustrated in, forexample, FIG. 4D). The first inorganic thin film IOL1 may be defined asa lower inorganic thin film, and the rest of the inorganic thin filmsmay be defined as upper inorganic thin films.

The thin film encapsulation layer TFE1 includes n−1 organic thin filmsOL1 to OLn−1. Here, the n−1 organic thin films OL1 to OLn−1 and the ninorganic thin films IOL1 to IOLn may be alternately disposed withrespect to each other. Each of the n−1 organic thin films OL1 to OLn−1may have a thickness greater than that of each of the n inorganic thinfilms IOL1 to IOLn.

Each of the n inorganic thin films IOL1 to IOLn may has a single layeredstructure formed of one material or a multi-layered structurerespectively formed of materials different from each other. Each of then−1 organic thin films OL1 to OLn−1 may be formed by depositing organicmonomers. The organic monomers may be, for example, acryl-basedmonomers. In an embodiment of the inventive concept, the thin filmencapsulation layer TFE1 may further include an n-th organic thin film(e.g., when the thin film encapsulation layer TFE1 further includes ann-th organic thin film, the total number of organic thin films may beequal to the total number of the inorganic thin films).

Referring now to FIGS. 5B and 5C, the inorganic thin films of each ofthe thin film encapsulation layers TFE2 and TFE3 may be formed of thesame material or materials different from each other and have the samethickness or thicknesses different from each other. The organic thinfilms of each of the thin film encapsulation layers TFE2 and TFE3 may beformed of the same organic material or organic materials different fromeach other and have the same thickness or thicknesses different fromeach other.

As illustrated in FIG. 5B, the thin film encapsulation layer TFE2 mayinclude the first inorganic thin film IOL1, the first organic thin filmOL1, the second inorganic thin film IOL2, the second organic thin filmOL2, and the third inorganic thin film IOL3, which are successivelylaminated.

The first inorganic thin film IOL1 may have a two-layered structure. Afirst sub layer S1 of the first inorganic thin film IOL1 may be alithium fluoride layer, and a second sub layer S2 may be an aluminumoxide layer. The first organic thin film OL1 may be a first organicmonomer layer, the second inorganic thin film IOL2 may be a firstsilicon nitride layer, the second organic thin film OL2 may be a secondorganic monomer layer, and the third inorganic thin film IOL3 may be asecond silicon nitride layer.

As illustrated in FIG. 5C, the thin film encapsulation layer TFE3 mayinclude a first inorganic thin film IOL10, a first organic thin filmOL1, and a second inorganic thin film IOL20, which are successivelystacked (or laminated). The first inorganic thin film IOL10 may have atwo-layered structure. A first sub layer S10 may be a lithium fluoridelayer, and a second sub layer S20 may be a silicon oxide layer. Thefirst organic thin film OL1 may be an organic monomer, and the secondinorganic thin film IOL20 may have a two-layered structure. The secondinorganic thin film IOL20 may include a first sub layer S100 and asecond sub layer S200, which are deposited under deposition environmentsdifferent from each other. The first sub layer S100 may be depositedunder a lower power condition, and the second sub layer S200 may bedeposited under a high power condition. Each of the first sub layer S100and the second sub layers S200 may be a silicon nitride layer.

FIG. 6A is a cross-sectional view of the touch sensing unit TS accordingto an embodiment of the inventive concept. FIGS. 6B to 6E are plan viewsof the touch sensing unit TS according to an embodiment of the inventiveconcept at different stages (acts/steps) during a manufacturing process.

As illustrated in FIG. 6A, the touch detection layer TS includes a firstconductive layer TS-CL1, a first insulation layer TS-IL1 (hereinafter,referred to as a first touch insulation layer), a second conductivelayer TS-CL2, and a second insulation layer TS-IL2 (hereinafter,referred to as a second touch insulation layer). The first conductivelayer TS-CL1 may be directly disposed on the thin film encapsulationlayer TFE. For example, the plastic film, the glass substrate, and/orthe plastic substrate may not be disposed between the first conductivelayer TS-CL1 and the thin film encapsulation layer TFE.

Each of the first conductive layer TS-CL1 and the second conductivelayer TS-CL2 may have a single-layered structure or a multi-layeredstructure in which a plurality of layers are stacked along the thirddirectional axis DR3. The conductive layer having the multi-layeredstructure may include a transparent conductive layer and at least twometal layers. The conductive layer having the multi-layered structuremay include metal layers formed of metals different from each other. Thetransparent conductive layer may include indium tin oxide (ITO), indiumzinc oxide (IZO), zinc oxide (ZnO), and/or indium tin zinc oxide (ITZO),PEDOT, a metal nano wire, and/or graphene. The metal layer may be formedof molybdenum, silver, titanium, copper, aluminum, and/or an alloythereof.

Each of the first and second conductive layers TS-CL1 and TS-CL2 mayinclude a plurality of patterns. Hereinafter, a structure in which thefirst conductive layer TS-CL1 includes first conductive patterns, andthe second conducive layer TS-CL2 includes second conductive patternswill be described. Each of the first and second conductive patterns mayinclude touch electrodes and touch signal lines.

Each of the first and second touch insulation layers TS-IL1 and TS-IL2may be formed of inorganic and/or organic material. The inorganicmaterial may include at least one oxide, such as titanium oxide, siliconoxide, silicon oxide nitride, zirconium oxide and/or hafnium oxide. Theorganic material may include at least one selected from an acrylic-basedresin, a methacrylic-based resin, a polyisoprene-based resin, avinyl-based resin, an epoxy-based resin, a urethane-based resin, acellulose-based resin, a siloxane-based resin, a polyimide-based resin,a polyamide-based resin, and a perylene-based resin.

Each of the first and second touch insulation layers TS-IL1 and TS-IL2may have a single-layer or a multi-layered structure. Each of the firstand second touch insulation layers TS-IL1 and TS-IL2 may include atleast one of an inorganic layer and an organic layer. The inorganiclayer and the organic layer may each independently be formed through achemical vapor deposition method.

In the current embodiment, at least one of the first touch insulationlayer TS-IL1 and the second touch insulation layer TS-IL2 includes atleast one inorganic layer having a density of about 2.05 g/cm³ to about2.4 g/cm³. This embodiment will be described later in more detail.

In some embodiments, the first touch insulation layer TS-IL1 insulatesthe first and second conductive layers TS-CL1 and TS-CL2 from eachother, but the embodiment of the inventive concept is not limitedthereto. The first touch insulation layer TS-IL1 may be formed in anysuitable shape, according to the shapes of the first and secondconductive patterns. In some embodiments, the first touch insulationlayer TS-IL1 may entirely cover the thin film encapsulation layer TFE ormay include a plurality of insulation patterns. The plurality ofinsulation patterns may be enough to overlap first connection parts CP1and/or second connection parts CP2 (illustrated in, for example, FIGS.6B-6E).

Although a two-layered touch sensing unit is illustrated as an examplein the current embodiment, the embodiment of the inventive concept isnot limited thereto. A single layer touch sensing unit may include aconductive layer and an insulation layer covering the conductive layer.The conductive layer may include touch sensors and touch signal linesconnected to the touch sensors. The single layer touch sensing unit mayacquire coordinate information in a self cap (e.g., self-capacitive)manner.

As illustrated in FIG. 6B, the touch sensing unit TS may include firsttouch electrodes TE1-1 to TE1-3, first touch signal lines SL1-1 to SL1-3connected to the first touch electrodes TE1-1 to TE1-3, second touchelectrodes TE2-1 to TE2-3, and second touch signal lines SL2-1 to SL2-3connected to the second touch electrodes TE2-1 to TE2-3. The touchsensing unit TS including three first touch electrodes TE1-1 to TE1-3and three first touch signal lines SL1-1 to SL1-3 is illustrated as anexample.

Each of the first touch electrodes TE1-1 to TE1-3 may have a mesh shape(e.g., a mesh pattern) in which a plurality of touch openings isdefined. Each of the first touch electrodes TE1-1 to TE1-3 includes aplurality of first touch sensor parts SP1 and a plurality of connectionparts CP1. The first touch sensor parts SP1 are arranged in the firstdirection DR1. Each of the first connection parts connects two firsttouch sensor parts SP1, which are adjacent to each other in the firstdirection DR1, of the first touch sensor parts SP1. In some embodiments,each of the first touch signal lines SL1-1 to SL1-3 may also have a meshshape (e.g., a mesh pattern).

The second touch electrode TE2-1 and TE2-3 may be insulated from thefirst touch electrodes TE1-1 to TE1-3 and may cross the first touchelectrodes TE1-1 to TE1-3. Each of the second touch electrodes TE2-1 toTE2-3 may have a mesh shape (e.g., a mesh pattern) in which a pluralityof touch openings is defined. Each of the second touch electrodes TE2-1to TE2-3 includes a plurality of second touch sensor parts SP2 and aplurality of second connection parts CP2. The second touch sensor partsSP2 are arranged in the second direction DR2. Each of the secondconnection parts CP2 connects two second touch sensor parts SP2, whichare adjacent to each other in the second direction DR2, of the secondtouch sensor parts SP2. Each of the second touch signal lines SL2-1 orSL2-3 may also have a mesh shape (e.g., a mesh pattern).

The first touch electrode TE1-1 to TE1-3 and the second touch electrodeTE2-1 to TE2-3 may be capacitively coupled to each other. Since touchdetection signals are applied to the first touch electrodes TE1-1 toTE1-3, capacitors may be disposed between the respective first touchsensor parts SP1 and the second touch sensor parts SP2.

Portions of the plurality of first touch sensor parts SP1, the pluralityof first connection parts CP1, and the first touch signal lines SL1-1 toSL1-3 and portions of the plurality of second touch sensor parts SP2,the plurality of second connection parts CP2, and the second touchsignal lines SL2-1 to SL2-3 may be formed by patterning the firstconductive layer TS-CL1 of FIG. 6A, and the other portions (e.g.,remaining portions of the aforementioned elements) may be formed bypatterning the second conductive layer TS-CL2 of FIG. 6A.

To electrically connect (e.g., couple) the conductive patterns disposedon layers different from each other, a contact hole passing through thefirst touch insulation layer TS-IL1 of FIG. 6A may be defined.Hereinafter, the touch sensing unit TS according to an embodiment of theinventive concept will be described with reference to FIGS. 6C to 6E.

Referring to FIG. 6C, the first conductive patterns may be disposed onthe thin film encapsulation layer TFE. The first conductive patterns mayinclude bridge patterns (or bridge parts) CP2. The bridge patterns CP2may be directly disposed on the thin film encapsulation layer TFE. Thethin film encapsulation layer TFE covering the display area DA will bedescribed as an example. The bridge patterns CP2 may correspond to thesecond connection parts CP2 of FIG. 6B.

As illustrated in FIG. 6D, the first touch insulation layer TS-IL1covering the bridge patterns CP2 may then be disposed on the thin filmencapsulation layer TFE. Contact holes CH that partially expose thebridge patterns CP2 are defined in the first touch insulation layerTS-IL1. The contact holes CH may be formed through a photolithographyprocess.

As illustrated in FIG. 6E, the second conductive patterns may then bedisposed on the first touch insulation layer TS-IL1. The secondconductive patterns may include the plurality of first touch sensorparts SP1, the plurality of first connection parts CP1, the first touchsignal lines SL1-1 to SL1-3, the plurality of second touch sensor partsSP2, and the second touch signal lines SL2-1 to SL2-3. In someembodiments, the second touch insulation layer TS-IL2 covering thesecond conductive patterns is disposed on the first touch insulationlayer TS-IL1.

In an embodiment of the inventive concept, the first conductive patternsmay include first touch electrodes TE1 to TE1 and first touch signallines SL1-1 to SL1-3. The second conductive patterns may include secondtouch electrodes TE2-1 to TE2-3 and second touch signal lines SL2-1 toSL2-3. In some embodiments, the contact holes CH may not be defined inthe first touch insulation layer TS-IL1.

Also, in an embodiment of the inventive concept, the first conductivepatterns and the second conductive patterns may be switched with eachother. For example, the second conductive patterns may include thebridge patterns CP2.

FIG. 7A is a partial enlarged view of an area AA of FIG. 6E. FIG. 7B isa partial cross-sectional view of FIG. 6A (cut along II-II′). FIG. 7C isa partial cross-sectional view of FIG. 6A (cut along I-I′). Hereinafter,the display module DM will be described in more detail with reference toFIGS. 7A to 7C.

As illustrated in FIG. 7A, the first touch sensor part SP1 overlaps thenon-emission area NPXA. The first touch sensor part SP1 includes aplurality of first vertical portions SP1-C extending in the firstdirection DR1 and a plurality of horizontal portions SP1-L extending inthe second direction DR2. The plurality of first vertical portions SP1-Cand the plurality of first horizontal portions SP1-L may be defined as amesh line (e.g., may have a mesh pattern). The mesh line may have a linewidth of several micrometers.

The plurality of first vertical portions SP1-C and the plurality offirst horizontal portions SP1-L may be connected to each other to definea plurality of openings TS-OP. For example, the first touch sensor partSP1 may have a mesh shape (e.g., a mesh pattern) having the plurality oftouch openings TS-OP. Although a structure in which the touch openingsTS-OP correspond to the emission areas PXA (in a one-to-onerelationship) is illustrated, the embodiment of the inventive concept isnot limited thereto. One touch opening TS-OP may correspond to two ormore emission areas PXA.

Each of the first connection parts CP1, the first touch signal linesSL1-1 to SL1-3, the second touch sensor parts SP2, the second connectionparts CP2, and the second touch signal lines SL2-1 to SL2-3 may includehorizontal portions and vertical portions.

As illustrated in FIGS. 7B and 7C, the second connection parts CP2 maybe directly disposed on the thin film encapsulation layer TFE. The firsttouch insulation layer TS-IL1 covering the second connection parts CP2may also be directly disposed on the thin film encapsulation layer TFE(or portions of the first touch insulation layer TS-IL1 may be directlydisposed on the thin film encapsulation layer TFE). The first touchinsulation layer TS-IL1 overlaps at least the display area DA. The firsttouch sensor parts SP1, the second touch sensor parts SP2, and the firstconnection parts CP1 may be directly disposed on the first touchinsulation layer TS-IL1.

The second touch insulation layer TS-IL2 (or portions thereof) may bedirectly disposed on the first touch insulation layer TS-IL1 to coverthe first touch sensor part SP1, the second touch sensor parts SP2, andthe first connection parts CP1. The second touch insulation layer TS-IL2overlaps at least the display area DA.

The first touch sensor parts SP1, the first connection parts CP1, thesecond touch sensor parts SP2, and the second connection parts CP2,which respectively have three-layered structure, are illustrated as anexample in FIGS. 7B and 7C. For example, each of the first touch sensorparts SP1, the first connection parts CP1, the second touch sensor partsSP2, and the second connection parts CP2 may have a three-layeredstructure of titanium/aluminum/titanium.

FIG. 8A is a cross-sectional view illustrating bubble defects occurringin the display apparatus DD. FIG. 8B is a photograph illustrating thebubble defects occurring in the display apparatus DD. FIG. 9 is a graphillustrating bubble defects depending on a layer density.

A reliability assessment was performed on a display apparatus that wasthe same as (or substantially the same as) the display apparatus DD ofFIG. 2 under severe conditions. The reliability assessment was performedunder a temperature of about 80 degrees to about 90 degrees Celsius andhumidity of about 80% to about 90%.

As illustrated in FIGS. 8A and 8B, bubbles were collected on aninterface between a window WM a third adhesion member AM3. The bubbleswere investigated and most were determined to be formed of nitrogenand/or hydrogen. For example, nitrogen and hydrogen may occupy about 80%to about 90% of the bubbles. The bubbles containing a very small amountof carbon dioxide, carbon monoxide, and/or methane were also analyzed.

Samples according to Experimental examples 1 to 8 were manufactured forassessing the reliability of the display apparatus under the severeconditions. Results of the experiments are shown in Table 1 below. InTable 1, “X” indicates the absence of a layer or bubbles, and “0”indicates the presence of a layer or bubbles.

TABLE 1 Second First touch touch insulation insulation First layerSecond layer conductive (inorganic conductive (organic Bubble layerlayer) layer layer) generation Experimental X X X X X example 1Experimental ◯ ◯ ◯ ◯ ◯ example 2 Experimental ◯ ◯ ◯ X ◯ example 3Experimental ◯ ◯ X X ◯ example 4 Experimental ◯ X X X X example 5Experimental X ◯ X X ◯ example 6 Experimental X ◯ X X X example 7Experimental X X X ◯ X example 8

The Experimental examples 1 to 6 were performed using a displayapparatus substantially similar to the one illustrated in FIG. 2.However, the touch sensing units (reference symbol TS of FIG. 6A, forexample) were different from each other in structure. In theExperimental example 1, the touch sensing unit TS was omitted. In theExperimental examples 2 to 6, portions of the first touch insulationlayer (e.g., the inorganic layer), the second conductive layer, and thesecond touch insulation layer (e.g., the organic layer) were omitted.

In the Experimental example 7, a glass substrate on which a single layerinorganic layer was formed was applied, instead of the display module(reference symbol DM of FIG. 2, for example). In the Experimentalexample 8, a glass substrate on which a single layer organic layer wasformed was applied, instead of the display module DM.

In the Experimental examples 1 to 8, 1.90 g/cm³ of a silicon nitridelayer formed through a chemical vapor deposition (PECVD) method wasapplied as the first touch insulation layer (the inorganic layer), andan acryl-based organic layer formed through a slit coating method wasapplied as the second touch insulation layer (the organic layer).

In light of the generation of the bubbles in the Experimental examples 2to 4 and 6, it is believed, without being bound by any particulartheory, that the generation of bubbles is related to the inorganiclayer. However, when comparing the Experimental examples 6 (bubblesformed) and 7 (bubbles not formed) to each other (both Experimentalexamples 6 and 7 having the same layer composition with respect to thefirst conductive layer, first touch insulation layer, second conductivelayer, and second touch insulation layer), it is seen that thegeneration of bubbles is not dependent on the single condition such asthe inorganic layer, but is also related to the thin film encapsulationlayer (e.g., in Experimental example 7, the thin film encapsulationlayer was not formed). It is presumed that a generation of seed (e.g.,bubble seed) is depended on the thin film encapsulation layer and theinorganic layer.

Based on the amount of bubbles generated in the Experimental examples 2to 4 and 6, it is presumed, without being bound by any particulartheory, that the bubbles are not introduced from the outside, but aregenerated through a reaction between seed and organic materials. It ispresumed that the seed is generated when the inorganic layer is formedon the thin film encapsulation layer. The organic materials may beincluded in the second touch insulation layer or the second adhesionmember (reference symbol AM2 of FIG. 2, for example) or the thirdadhesion member (reference symbol AM3 of FIG. 2, for example).

An additional experiment was performed on the samples according to theExperimental examples 2 and 3. Samples according to Experimentalexamples 2 and 3 had substantially the same structure, except that theorganic layer was not formed in the Experimental example 3. A bubblegeneration time was measured by using the samples according to theExperimental examples 2 and 3 (four samples each).

TABLE 2 24 120 168 264 336 500 (hour) (hour) (hour) (hour) (hour) (hour)Experimental 0/4 3/4 4/4 4/4 4/4 4/4 example 3 Experimental 3/4 4/4 4/44/4 4/4 4/4 example 2

The reliability assessment was performed on each of the four samplesaccording to Experimental example 2 and each of the four samplesaccording to Experimental example 3. Although bubbles were not generatedafter 24 hours in any of the samples of the Experimental example 3,bubbles were generated after 24 hours in three samples of the foursamples of the Experimental example 2.

According to the experimental results shown in Table 2 above, it isbelieved, without being bound by any particular theory, that the organiclayer may cause or at least increase the generation of the bubbles. Forexample, it is believed that the seed may react with the organicmaterials of the second touch insulation layer or the second adhesionmember (reference symbol AM2 of FIG. 2, for example) or the thirdadhesion member (reference symbol AM3 of FIG. 2, for example) inExperimental example 2. It is believed that the seed may react with theorganic materials of the second adhesion member (reference symbol AM2 ofFIG. 2, for example) or the third adhesion member (reference symbol AM3of FIG. 2, for example) in Experimental example 3.

An additional experiment was also performed on the samples of theExperimental examples 9 and 10. Bubble generation time was measured byusing the samples according to the Experimental examples 9 and 10 (fivesamples each). The results are shown in Table 3 below.

TABLE 3 24 48 72 196 360 500 (hour) (hour) (hour) (hour) (hour) (hour)Experimental 0/5 0/5 1/5 1/5 2/5 2/5 example 9 Experimental 0/5 1/5 1/52/5 2/5 2/5 example 10

Each of the samples of the Experimental examples 9 and 10 had the same(or substantially the same) structure as that of the Experimentalexample 2 (e.g., the same structure as that of the display apparatusillustrated in FIG. 2). In the sample of Experimental example 9, anoptically clear adhesive (OCA) manufactured by 3M Purification Inc., wasapplied as the second adhesion member AM2 and the third adhesion memberAM3. In the sample of Experimental example 10, an optically clearadhesive (OCA) manufactured by TMS was applied as the second adhesionmember AM2 and the third adhesion member AM3. The OCAs from theabove-described manufactures have compositions different from eachother.

According to the experimental results shown in Table 3 above, bubblegeneration times are different depending on the compositions of theadhesion members. Also, it can be seen that the amount of bubblesgenerated after the same amount of time has passed is also differentdependent on the compositions of the adhesion members.

The samples in which the inorganic layer varies in density weremanufactured for assessing the reliability. Here, the samples having thesame (or substantially the same) structure as that of the Experimentalexample 2 were manufactured, except the inorganic layer for each samplevaried in density.

A silicon nitride layer may be formed by using a mixed gas of silane(SiH₄), nitrogen (N₂), hydrogen (H₂), and ammonia (NH₃) through achemical vapor deposition process. A flow rate for each of the silane(SiH₄) and the hydrogen (H₂) may have affect the density of theresulting silicon nitride layer. Also, variations in power and pressurewithin the deposition chamber may affect the density of the siliconnitride layer. In forming the above-described samples, factors believedto have an effect on the composition of the resulting layers wereequally maintained among the samples, except that the flow rate of thesilane (SiH₄) was adjusted to form inorganic layers having differentdensities according to the samples.

The bar graph illustrated in FIG. 9 represents generation of bubbledefects depending on the layer density. In the sample displayapparatuses in which the silicon nitride layer has a layer density ofabout 2.05 g/cm³ or more, bubbles do not appear to be generated.

Without being bound by any particular theory, it is believed that thebubbles are not generated in the samples having the silicon nitridelayer density of about 2.05 g/cm³ or more due to non-reaction betweenthe seed and the organic material, because the seed generated while thesilicon nitride layer is formed is sealed by the high-density siliconnitride layer.

In contrast, in the display apparatus including the inorganic layerhaving the layer density of about 2.05 g/cm³ or less, the seeds may passthrough a low-density inorganic layer to reach the second touchinsulation layer TS-IL2 and the organic adhesion layers (e.g., referencesymbols AM2 and AM3 of FIG. 2). In this case, it is believed that theseeds react with the second touch insulation layer TS-IL2 and theorganic adhesion layers AM2 and AM3 to generate bubbles.

When the bubbles are generated in the second touch insulation layerTS-IL2, they may pass through the second adhesion member AM2, theoptical member LM, and the third adhesion member AM3, and then arecollected on an interface between the window WM and the third adhesionmember AM3. Also, when the bubbles are generated in the second adhesionmember AM2 and the third adhesion member AM3, they also may be collectedon the interface between the window WM and the third adhesion memberAM3.

As the inorganic layer gradually increases in density, flexibility ofthe layer gradually decreases. Thus, the inorganic layer may have adensity of about 2.4 g/cm³ or less. When the inorganic layer has adensity within this range, the generation of cracks in the inorganiclayer, caused by stress applied from the outside, may be prevented orreduced.

In the current embodiment, at least one of the first touch insulationlayer TS-IL1 and the second touch insulation layer TS-IL2, as theselayers are described with, for example, reference to FIG. 6A, mayinclude at least one inorganic layer having a density of about 2.05g/cm³ to about 2.4 g/cm³. Here, the generation of the above-describedbubbles may be suppressed or reduced, and the occurrence of the cracksin the first touch insulation layer TS-IL1 and the second touchinsulation layer TS-IL2 may be prevented or reduced.

In an embodiment of the inventive concept, each of the first touchinsulation layer TS-IL1 and the second touch insulation layer TS-IL2 mayinclude the silicon nitride layer having the above-described density.

In an embodiment of the inventive concept, the first touch insulationlayer TS-IL1 may include the silicon nitride layer having theabove-described density. Here, the second touch insulation layer TS-IL2may be an organic layer. When an inorganic layer having a density lessthan the above-described density is formed, bubbles may be generatedduring the formation of the second touch insulation layer TS-IL2. Toprevent or reduce the possibility of the bubbles being generated and toimprove flexibility, the second touch insulation layer TS-IL2 may be anorganic layer.

In an embodiment of the inventive concept, the second touch insulationlayer TS-IL2 may include the silicon nitride layer having theabove-described density. When the second touch insulation layer TS-IL2has a multi-layered structure, the silicon nitride layer having theabove-described density may be the uppermost layer. Here, the firsttouch insulation layer TS-IL1 may include an organic layer and/orinorganic layer.

FIG. 10A is a cross-sectional view of a display apparatus DD-2 accordingto an embodiment of the inventive concept. FIG. 10B is an enlargedcross-sectional view of the display module DM-1 of the display apparatusDD-2 according to an embodiment of the inventive concept. FIG. 11 is across-sectional view of a display apparatus DD-3 according to anembodiment of the inventive concept. Hereinafter, detailed descriptionsof the same constituent elements as those described with reference toFIGS. 1 to 9 will not be provided.

As illustrated in FIGS. 10A and 10B, the display apparatus DD-2 includesa protection film PM, a display module DM-1, a touch panel TSP, a windowWM, a first adhesion member AM1, a second adhesion member AM2, and athird adhesion member AM3. The display module DM-1 may include anorganic light emitting display panel DP and a reflection preventionlayer RPL. The reflection prevention layer RPL may be directly disposedon the organic light emitting display panel DP.

The reflection prevention layer RPL may include conductive layersRPL-ML1 and RPL-ML2, which respectively overlap the display area DA andthe non-display area NDA, and insulation layers RPL-IL1 and RPL-IL2,which respectively overlap the display area DA and the non-display areaNDA. The reflection prevention layer RPL including two conductive layersRPL-ML1 and RPL-ML2 and two insulation layers RPL-IL1 and RPL-IL2 isillustrated as an example, but embodiments of the present disclosure arenot limited thereto.

The conductive layers RPL-ML1 and RPL-ML2 and the insulation layersRPL-IL1 and RPL-IL2 may be alternately laminated. However, an embodimentof the inventive concept is not limited to this lamination order. Thefirst conductive layer RPL-ML1 may include a metal having an absorptionrate of about 30% or more. The first conductive layer RPL-ML1 may beformed of a material having a refractive index of about 1.5 to about 7and an absorption coefficient k of about 1.5 to about 7. The firstconductive layer RPL-ML1 may be formed of at least one selected fromchrome (Cr), molybdenum (Mo), tungsten (W), titanium (Ti), nickel (Ni),cobalt (Co), copper oxide (CuO), titanium nitride (TiNx), and nickelsulfide (NiS). The first conductive layer RPL-ML1 may be a metal layerformed of one of the above-described materials. In some embodiments, thesecond conductive layer RPL-ML2 may also include the above-describedmetals.

Each of the first insulation layer RPL-IL1 and the second insulationlayer RPL-IL2 may be formed of one selected from silicon dioxide (SiO₂),titanium dioxide (TiO₂), lithium fluoride (LiF), calcium fluoride(CaF₂), magnesium fluoride (MaF₂), silicon nitride (SiN_(x)), tantalumoxide (Ta₂O₅), niobium oxide (Nb₂O₅), silicon carbon nitride (SiCN),molybdenum oxide (MoO_(x)), iron oxide (FeO_(x)), and chromium oxide(CrO_(x)). Light OL incident from the outside is partially reflected bythe first conductive layer RPL-ML1 (hereinafter, the light reflected bythe first conductive layer RPL-ML1 is referred to as a first reflectedlight RL1) and the second conductive layer RPL-ML2 (hereinafter, thelight reflected by the second conductive layer RPL-ML2 is referred to asa second reflected light RL2).

The first insulation layer RPL-IL1 may adjust a phase of light passingthrough the first insulation layer RPL-IL1, such that the firstreflected light RL1 and the second reflected light RL2 have a phasedifference of about 180° therebetween. Thus, the first reflected lightRL1 and the second reflected light RL2 may be offset

Thickness and material for each of the first conductive layer RPL-ML1,the second conductive layer RPL-ML2, the first insulation layer RPL-IL1,and the second insulation layer RPL-IL2 may be selected to satisfy (orbe suitable for) conditions for instructive interference between thefirst reflected light RL1 and the second reflected light RL2. However,an embodiment of the inventive concept is not particularly limitedthereto. In some embodiments, the reflection prevention layer RPL mayfurther include a black matrix BM.

To prevent or reduce the possibility of bubbles being generated duringthe formation of the reflection prevention layer RPL, at least one ofthe first insulation layer RPL-IL1 and the second insulation layerRPL-IL2 may include an inorganic layer having a density of about 2.05g/cm³ to about 2.4 g/cm³. For example, each of the first insulationlayer RPL-IL1 and the second insulation layer RPL-IL2 may include asilicon nitride layer having the above-described density.

As illustrated in FIG. 11, the display apparatus DD-3 includes aprotection film PM, a display module DM-2, a window WM, a first adhesionmember AM1, and a second adhesion member AM2. The display module DM-2may include an organic light emitting display panel DP, a touch sensingunit TS, and a reflection prevention layer RPL. The touch sensing unitTS may be directly disposed on the organic light emitting display panelDP, and the reflection prevention layer RPL may be directly disposed onthe touch sensing unit TS.

The touch sensing unit TS may have the same structure as that describedwith reference to FIGS. 1 to 9, and the reflection prevention layer RPLmay have the same structure as that described with reference to FIGS.10A and 10B.

As described above, the inorganic layer having a density of about 2.05g/cm³ to about 2.4 g/cm³ may seal the seed that may otherwise cause thegeneration of the bubbles. For example, the seed may be sealed adjacentto the thin film encapsulation layer.

The inorganic layer may prevent or reduce the seed from approaching theorganic layer. Thus, the reaction between the seed and the organic layermay be prevented or reduced, and the generation of the bubbles may besuppressed or reduced. Therefore, the delamination between the organicadhesion member and the window may be reduced.

As used herein, the terms “use,” “using,” and “used” may be consideredsynonymous with the terms “utilize,” “utilizing,” and “utilized,”respectively.

In addition, the terms “substantially,” “about,” and similar terms areused as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be recognized by those of ordinary skill inthe art.

Also, any numerical range recited herein is intended to include allsubranges of the same numerical precision subsumed within the recitedrange. For example, a range of “1.0 to 10.0” is intended to include allsubranges between (and including) the recited minimum value of 1.0 andthe recited maximum value of 10.0, that is, having a minimum value equalto or greater than 1.0 and a maximum value equal to or less than 10.0,such as, for example, 2.4 to 7.6. Any maximum numerical limitationrecited herein is intended to include all lower numerical limitationssubsumed therein and any minimum numerical limitation recited in thisspecification is intended to include all higher numerical limitationssubsumed therein. Accordingly, Applicant reserves the right to amendthis specification, including the claims, to expressly recite anysub-range subsumed within the ranges expressly recited herein.

Although the example embodiments of the present inventive concept havebeen described herein, it will be apparent to those skilled in the artthat various modifications and variations can be made in the inventiveconcept. Thus, it is intended that the present disclosure covers themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

What is claimed is:
 1. A display apparatus comprising: an organic lightemitting display panel comprising a base layer, a transistor on the baselayer, a light emitting diode electrically connected to the transistor,and a thin film encapsulation layer on the light emitting diode; a touchsensing unit on the thin film encapsulation layer, the touch sensingunit comprising: a conductive layer on the thin film encapsulationlayer; a silicon nitride layer directly on the conductive layer, eachsilicon nitride layer in the touch sensing unit having a density ofabout 2.05 g/cm³ to about 2.4 g/cm³; and an organic layer on the siliconnitride layer; and a window facing the organic light emitting displaypanel, with the touch sensing unit being between the window and theorganic light emitting display panel, wherein the thin filmencapsulation layer comprises: a plurality of inorganic thin films; andat least one organic thin film between the plurality of inorganic thinfilms.
 2. The display apparatus of claim 1, wherein the silicon nitridelayer covers the conductive layer.
 3. The display apparatus of claim 1,wherein the organic layer is contacted with the conductive layer.
 4. Thedisplay apparatus of claim 1, further comprising an organic adhesionlayer configured to couple the window to the organic light emittingdisplay panel.
 5. The display apparatus of claim 1, further comprising apolarizing film between the touch sensing unit and the window.
 6. Thedisplay apparatus of claim 1, wherein the conductive layer comprisessensors having a mesh shape.
 7. The display apparatus of claim 1,wherein the organic light emitting display panel comprises an emissionarea and a non-emission area adjacent to the emission area, wherein theconductive layer has a mesh pattern and overlaps the non-emission area.8. The display apparatus of claim 1, wherein the conductive layercomprises: a first conductive layer on the thin film encapsulationlayer; and a second conductive layer on the thin film encapsulationlayer, the second conductive layer being different from the firstconductive layer.
 9. The display apparatus of claim 8, wherein a firstlight reflected by the first conductive layer and a second lightreflected by the second conductive layer have a phase difference ofabout 180° therebetween.
 10. The display apparatus of claim 9, wherein:a first inorganic layer is between the first conductive layer and thesecond conductive layer, and a second inorganic layer is on the firstconductive layer and the second conductive layer.
 11. The displayapparatus of claim 1, wherein the conductive layer comprises sensorsthat define a single layer.
 12. The display apparatus of claim 11,wherein the sensors have a multi-layered structure.
 13. The displayapparatus of claim 1, wherein the window comprises a plastic film. 14.The display apparatus of claim 13, wherein the organic layer comprisesan organic adhesion layer contacting the window.
 15. A display apparatuscomprising: an organic light emitting display panel comprising a baselayer, a transistor on the base layer, a light emitting diodeelectrically connected to the transistor, and a thin film encapsulationlayer on the light emitting diode; a conductive layer on the thin filmencapsulation layer; a plurality of silicon nitride layers on the thinfilm encapsulation layer, each of the plurality of silicon nitridelayers having a density of about 2.05 g/cm³ to about 2.4 g/cm³; anorganic layer on at least one of the plurality of silicon nitridelayers; and a window facing the organic light emitting display panel,with the conductive layer, the plurality of silicon nitride layers, andthe organic layer between the window and the organic light emittingdisplay panel.